The most common emerging heavy metals and dyes with negative effects and limits according to the World Health Organization (WHO)^11–13.

Contaminants		Health hazards	Permissible limit (mg L−1)
Metal ions	Cr6+	Headache, nausea, carcinomas, and lung tumors	0.05
	Cu2+	Liver damage, muscle weakness, insomnia	2.5
	Ni2+	Dermatitis, lung cancer, and persistent asthma	2
	Ar3+	Lung and kidney cancer and nausea	0.01
	Cd2+	Emphysema, cancer and kidney damage	0.003
Dyes	Color	—	15 Pt. Co